Salvage pontoon



April 21, 1953 M. J. sTuRTEvANT 2,635,574

sALvAGE PoNTooN Filed June 22, 1949 JNVENToR. MARK J. STURTEVANT BY WMM@ ATTORNEY Patented Apr. 21, 1953 SALVAGE PONTO ON MarkJ. Sturtevant, St. Clair Shores, Mich., as-

signor to Wingfoot Corporation, Akron, Ohio, a corporation of Delaware Application June22, 1949, Serial No. 100,585

' 5 claims. (o1. 114-54) The present invention relates to a salvage device of the type disclosed in my Patent No. 2,451,002 granted October 12, 1948, for Salvage Apparatus. In fact, the device disclosed herein embodies, in the lifting chamber itself, substantially the same construction as in that patent but I have found that by a very simple modification of the valve mechanism disclosed in that patent I can eliminate a considerable portion of the construction used'for operating the valve, all of which will be more clearly understood as the description proceeds.

One object of this invention is to provide a salvage device having a valve which is normally balanced against inside-outside pressures on the chamber wall when the chamber is inflated to raise a sunken object through a body of water and starts its rise to the surface, the valve being provided with a restrictive passage which restricts the ow of air between the main chamber of the salvage device and an exteriorly arranged chamber having a flexible Wall connected to the valve for moving the valve to open position when the pressure in the last-mentioned chamber becomes greater than that within the first chamber, causing the valve inthe main chamber to qopen and release air from the chamber, which reduces surplus buoyancy resulting from changes in external water pressure on the contained air and thus decreases the rate of rise.

This invention uses a valvel acted upon by air Pressure in two different directions. The valve normally held closed under a predetermined pressure and until there is a differential of pressure between the two chambers, the valve remains closed. This can be done by a spring with exposed areas exactly balanced, which is the most desirable, or by predetermined closing pressure resulting from the upper area being greater` than the lower. 'salvage device, the pressure of the air within the salvage device is reduced at a rapid rate because I'of the reduced water pressure. If, therefore, the

However, upon tool rapid a rise of the vsalvage chamber is connected'with the chamber l Fig. 1 is a vertical sectionalview .through a ,n

device embodying the invention;

Fig. 2 is a vertical cross-sectional view through the'valve mechanism shown in Fig. 1; and

Fig. 3 is a cross-section through a modified form of valve stem.

The salvage device comprises a main flexible chamber I having Aa valve mechanism generally designated as 2, an air supply line for supplying air to the chamber' designated as 3, and a load connecting device 4 attached to the rim of the lower open end 5 of the chamber I for supporting the load 6 which in practice is the object to be raised from the body of water. This is, in general, the same construction as shown inY my aforesaid Patent 2,451,002. Y

The valve mechanism shown particularly in Fig. 2 is constructed as follows: The chamber I has an opening at the top thereof and two clamping rings 'I and 8 are arranged on opposite sides of the fabric of the chamber and held rmly clamped thereagainst by means of the bolts 9 and nuts I0. The ring 8 has at its inner edge a circular seat II against which the valve I2 is normally held by a spring I 3 abutting against a projection I4 on the Valve stem I5 and against a plate I6 held in adjusted position on the bolts 9 and the nuts I'I. Overlying the projecting portion I4 on the valve stem is a diaphragm I8 of flexible material clamped tothe valve stem by means of a nut I9 threaded on the stem I5 and this diaphragm is also connected at its outer periphery to the bolts 9 and is clamped rigidly between the flat clamping ring 20 and the fiat edge 2| of a dome-shaped wall 22 forming the upper part of the valve. Thenuts 23 are used for clamping the edges of the diaphragm securely in place.

Generally speaking.' the valve would have a ring-like member 24 connected by a cable 25 to vthe salvage vessel to permit the manual or mechanical raising and lowering of same other than by the operation of the air pressure itself, or the arrangement in Fig. 1 of the aforesaid patent rcould be employed but neither of these constructions form a p-art of the present invention. In effect, there are now two chambers provided with 'a main chamber which I have designated as I and which contains the air for raising the sunken Avessel or object and a chamber 26 formed by the SiieXible diaphragm I8 and the dome-shaped wall I in either direction. The spring I3 provides a normal closing pressure for the valve I2, which may be adjusted by adjusting the nuts I1 so that an appreciable amount of pressure will be required to open the valve.

In order to maintain the pressure in the two chambers substantially equal, I provide a passageway 21 extending through the valve stem I5. This is similar to that passageway 35 shown in the aforesaid patent, but in that patent the opening was made primarily for the purpose of equalizing the pressures in the two chambers and the size of this opening was not material. It was constructed to provide free -unobstructed passage of the air through the valve stem to permit the equalization at all times, thus creating a balanced valve- In order to open the valve in the aforesa-id patent, an inverted parachute, connected by a chain, cable or the like to the valve, opens the valve when the rate of rise is too great. In short, the drag on the converted parachute was employed to operate the cable to open the valve. It

.will readily be appreciated that such mechanism is complicated, adds materially to the cost and there is just that much more mechanism which is subject to deterioration and maintenance.

In the present invention, I have eliminated the parachute and all the connecting apparatus but have provided an opening 21 of' relatively small cross section which, while at the same time permitting the ow of air between the chambers to equalize the pressuresy this opening 21 will not permit a rapid flow of the air.y Therefore, when the salvage device rises at too fast a rate, there is a considerable drop in the pressure in the chamber I which cannotbe equalized rapidly by the ilow of air from the chamber 26 because the opening 21 is very small. This creates a greater pressure in the chamber 2B, which overcomes the pressure of the spring I3, and causes the valve to open and v air to escape from the chamber I to decrease the lift of the salvage device and slow down the rate of rise to a point where it is not dangerous or undesirable. As soon as the pressure is equalized again, the valve closes and air which is supplied through the air supply line to the chamber 3 is employed to increase the volume of air in the chamber I, if this becomes necessary.

The size of this passage 21 is dependent on a great many factors, namely the volume of the chamber I as compared to the volume of chamber 26, the area of the valve I2, the desired Spring pressure I3 and numerous other factors which can only be adequately determined by experimental work with a particular size of valve and salvage device. 'Ihe size of the air passage 21 depends upon several conditions and would have to be calculated for any particular Size of Salvage device. The various conditions to be taken into consideration would be the size. of the salvage device, the weight of the load to be lifted and the permissible rate of rise from which it would be necessary to calculate the size of the main valve, the size of the diaphragm chamber and the size of the passage 21. By using an adjustable device, hereinafter described, for changing the size of the passage, it is possible to avoid some of the calculations and rely solely upon nal adjustment of the size of the passage after the device has been constructed.

However, the effective size of this opening is preferably made adjustable so that the same valve mechanism can be used for containers of different sizes and for adjusting the ratefof flow through the passage under different operating conditions.

This construction is shown in Fig. 3 in which I have merely shown a valve stem 28 which is similar to the valve stem I5 and has an opening 29 similar to the opening 21 in the form shown in FigA 2. This valve stem has a portion extending downwardly beyond the threaded portion 36, which is similar to the threaded portion shown on the valve stem I5 at the lower end thereof. In other words, there is an extension 3l which will normally extend into the chamber I and this has' a needle valve 32 of any desired construction for .adjusting the effective size of the passage 29. Of course, this needle valve 32 may be arranged anywhere along the passage 2i) but is preferably arranged within the chamber I, whereby any small amount of leakage of air around the needle valve where it passes through the Wall of the extension 3l will not have any real detrimental effect. If it were placed at the center of the valve stem where it would be exposed to the water, there would be a tendency for air to leak out into the water as the air pressure would always be greater than the water pressure. This would probably not be too objectionable but, with the valve exposed to the water, there would be more tendency to corrode and prevent adjustment ofthe needle valve later on.

All of the results that Would be obtained by the mechanism eliminated from the previous patented structure are accomplished by the use of the restricted passage 21, thus greatly simplifying the device, yet maintaining its efliciency for the purposes set forth.

While I have illustrated one form of the invention, it will be apparent to those skilled in the art that various changes and modications may be .made therein without departing from the spirit or scope of the invention.

Having thus fully described my invention, what I claim and desire to secure by Letters Patent of the United States is;

1. In a salvage apparatus adapted to be used in bodies of water to raise sunlfzen objects, the combination with a container forming .an air chamber having an opening for the escape of air therefrom, and a valve mechanism secured to the edges of said opening, comprising a valve for closing said opening and positioned to be exposed to the exterior and interior pressures of the Water and the air respectively when in use, a

hollow body exterior of said chamber having a flexible portion exposed exteriorly to the pressure of the water when in use, said valve being connected to said Vflexible portion to move therewith and having a central opening of relatively small cross-section lfor restrictive now of air between said chamber and hollow body to normally balance the pressures in said chamber and hollow body, Said Opening being of such a small cross section that it materially restricts the flow of air from said hollow body to said chamber when said Salvage apparatus rises faster than desirable whereby to prevent rapid drop in pressure in said body. thus causing a greater pressure within said hollow body with respect to the pressure in .said chamber to thus move the valve to open position to permit the escape of air from said chamber.

2. A device as set forth in claim l in which there is provided an independent means for llQldIlg Said valve closed under a sufficient pressure .00 insure retaining the air in said chamber duringv rise of said salvage apparatus at the desired rate.

3. A device as set forth in claim 1 in which there is provided an independent adjustable pressure means for holding said valve closed under a suicient pressure to insure retaining the air in said salvage apparatus during rise of said chamber at the desired rate.

4. In a salvage device comprising a container forming an air chamber, a second container forming an air chamber exteriorly of said rst chamber having a movable wall, an opening in said first container, a valve for closing said opening and connected to said movable wall for movement therewith, a small restrictive passage between said chambers to permit slow flow of air therethrough to normally keep the pressures in said chambers equal when the salvage device is rising in a body of water at a rate no greater than desired but not sufficiently large to permit equalization of the pressures when the rate of rise is `excessive, said valve and movable wall being exposed to be acted on by the water surrounding said device in substantially equal amounts, whereby upon a material reduction of the air pressure in the first chamber the valve will be opened to permit escape of air therefrom to decrease the rate of rise of the device, there being means to normally hold the valve firmly against its seat.

5. A device as set forth in claim 4 in which said restrictive passage extends through said valve.

MARK J. STURTEVANT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 16,992 Thrush June 12, 1928 284,667 Powers Sept. l1, 1883 1,987,666 Carlson Jan. 15, 1935 2,215,387 Burkart Sept. 17, 1940 2,219,408 Benz et al Oct. 29, 1940 2,328,007 Griswold Aug. 31, 1943 2,399,326 Crot Apr. 30, 1946 2,451,002 Sturtevant Oct. 12, 1948 

